How Many Calories Do You Burn in a Half Marathon? Real Numbers & Practical Tips

Ever stood at the starting line wondering, “If I run 13.1 miles today, how many calories will I actually burn?” Whether you’re training for a PR, chasing a weight-loss goal, or just curious, understanding how many calories do you burn in a half marathon can help you plan fuel, recovery, and training more effectively.

Quick answer: calorie estimates for a half marathon

There isn’t a single number that fits everyone, but a simple and commonly used rule of thumb is: running burns about 0.63 kilocalories per pound of body weight per mile. Multiply that by 13.1 miles and you get a quick estimate.

Example calorie calculations

• 120 lb runner: 0.63 × 120 × 13.1 ≈ 990 kcal
• 150 lb runner: 0.63 × 150 × 13.1 ≈ 1,238 kcal
• 180 lb runner: 0.63 × 180 × 13.1 ≈ 1,485 kcal

So most runners will burn roughly 900 to 1,600 calories in a half marathon depending on weight, pace, terrain, and effort.

What affects calorie burn during 13.1 miles?

Calories burned depends on more than distance. Consider these variables:

• Body weight and composition: Heavier runners expend more energy moving their mass. Muscle mass also increases resting and active calorie use.
• Pace and intensity: Faster paces raise metabolic rate. A fast 1:20 half will burn differently than a relaxed 2:30 jog.
• Terrain and elevation: Hilly courses increase energy cost vs. flat routes.
• Weather and temperature: Hot or cold conditions force extra energy for thermoregulation.
• Gear and load: A heavy hydration pack or winter layers add to energy demand.
• Fitness level and efficiency: More economical runners use less energy at a given pace.

How to get a personalized calorie estimate

For more accuracy, use one of these methods:

• Multiply your weight (lbs) × 0.63 × 13.1 for a solid baseline.
• Use your GPS watch or running app that factors pace and heart rate—expect a margin of error of ±10–20%.
• Convert METs to calories if you know your pace and MET value: Calories = MET × body weight (kg) × hours.

Fueling during a half marathon: what to eat and when

In most cases you don’t need heavy fueling during a half, but fueling approach matters if you want to avoid bonking and optimize performance:

• For races under 90 minutes: water or electrolyte drink and a carbohydrate-rich breakfast 2–3 hours before the start is usually enough.
• For 90–120+ minute efforts: consume 30–60 grams of carbs per hour (gels, chews, sports drink) to maintain blood glucose and delay fatigue.
• Practice your race nutrition in long training runs to avoid stomach issues.

Training tips to increase calorie burn and performance

Want faster times and greater energy expenditure? Mix these into your training plan:

• Long runs: Build up to a 10–12 mile long run so the half marathon feels manageable.
• Tempo runs: Improve lactate threshold and increase sustained calorie burn.
• Intervals and speed work: Raise VO2 max and increase post-exercise calorie expenditure (EPOC).
• Strength training: Twice weekly full-body strength sessions boost muscle and metabolic rate.
• Cross-training: Cycling or swimming preserves aerobic fitness and reduces injury risk while burning calories.

For structured plans, check our internal workout routines page for sample schedules and progressions.

Recovery: refuel the right way after 13.1 miles

Recovery fuels adaptations, repairs tissue, and restores glycogen. Follow these guidelines:

• Within 30–45 minutes post-run: aim for 20–40 g of protein and 0.5–0.7 g carbs per pound of body weight (e.g., a sandwich + protein shake).
• Rehydrate with water and a sodium-containing drink if you sweat heavily.
• Prioritize sleep, mobility work, and light active recovery the day after a long race.

Want meal ideas and timing tips? Visit our nutrition guides for practical recovery meal plans.

Real-world examples: two runners, same distance, different burns

Consider Aisha (130 lbs, experienced) and Marcus (190 lbs, recreational):

• Aisha: 0.63 × 130 × 13.1 ≈ 1,075 kcal. Because she’s efficient and strong, her perceived effort is moderate and she recovers quickly.
• Marcus: 0.63 × 190 × 13.1 ≈ 1,572 kcal. He burns more calories due to greater weight and slightly slower pace on hills, so his refueling needs are higher.

Both should focus on individualized fueling and recovery rather than comparing raw numbers.

Practical tips to maximize fitness gains from your half marathon

• Use long runs as metabolic training—practicing pacing and fueling is as important as calorie burn.
• Don’t try new foods or gear on race day; experiment during training.
• Track trends, not single races: use weekly calorie balance and performance improvements for smarter goals.
• Pair running with resistance training to build lean mass and increase long-term calorie expenditure—see our wellness tips for recovery and sleep strategies.

Frequently Asked Questions

1. Is the “0.63 × weight × miles” rule accurate?

It’s a reliable rule of thumb for most runners and distances. It simplifies complex physiology into an easy estimate, but it doesn’t account for pace, terrain, or individual efficiency. Use it as a baseline and adjust with heart-rate or GPS watch data for greater precision.

2. How many calories should I eat after running a half marathon?

Aim to replace glycogen and provide protein for muscle repair: roughly 20–40 g protein and 0.5–0.7 g carbs per pound of body weight in the first few hours. Total calorie needs depend on your daily goal and training load.

3. Can I lose weight by running a half marathon?

A single half marathon burns a large number of calories, but sustainable weight loss depends on consistent calorie balance over weeks. Use races as milestones, combine training with strength work, and prioritize a modest calorie deficit that’s sustainable.

Conclusion: how many calories do you burn in a half marathon — and what to do next

So, how many calories do you burn in a half marathon? Most runners will burn roughly 900–1,600 calories depending on body weight, pace, and conditions. Use the 0.63 × weight × 13.1 formula for a quick estimate, adjust for your effort, and plan fueling and recovery accordingly.

Ready to turn that insight into action? Try a long-run fueling experiment this week, add two strength sessions to your plan, or check our workout routines and nutrition guides to build a personalized half marathon strategy. Share your race goal in the comments and I’ll suggest a practical tweak to your plan.

Call to action: Want a custom calorie and fueling plan for your weight and pace? Leave your current weekly mileage and race goal below — I’ll help you fine-tune it.